How can I enlarge a pic?

I hope that there is a way to enlarge a pic that I take with the Droid. It's fine as it is on the phone, but when I email it to myself to save on my computer or upload it to a social network it shows up way to small. I changed the setting to "Large" and I got a bigger frame for snapping pics but the size of the pic once it got on my computer didn't get any bigger.